Assuming you have already completed your island hopping adventure.
Outer islands.. virtually no nightlife.
(Kona being the exception)
Kauai is beautiful to visit (Waimea canyon, Wailua falls, Anini beach, etc. Nowhere is more serene and reflects Hawaii except for say Moloka'i.
Oahu is the gathering place. Lots of people, lots of overcrowded places to eat, visit and get overrun by tourists.
Maui- #2 most populous... Not as busy as Oahu and still has some beautiful places to visit off the beaten path.
Hawaii Island... Food... Places to visit... Things to do. The only place in Hawaii you can go from snow covered mountain to sunny seashore in a little more than a hour.
And for two beautiful ladies like yourselves, company is not going to be a problem!